Factors influencing adhesion of bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and yeast Pichia membranifaciens to wooden surfaces

Abstract

The aim of this study was to assess the potential of bacteria Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and yeast Pichia membranifaciens ZIM 2417 to adhere to wooden surfaces such as poplar (Populus sp.), Norway spruce (Picea abies), European beech (Fagus sylvatica), beech coated with the commercial Belinka oil food contact and disinfectant P3-oxonia active 150, and investigate their survival on the beech wood surface under different relative humidities (RH; 65%, 75%, 85%, 98%) and temperatures (10 °C, 20 °C, 27 °C/37 °C). To extend the research goals, the scanning electron microscopy (SEM) analysis was also performed. The adhesion was determined by the number of colony-forming units per mm2 of sample (CFU/mm2). Results showed that all tested bacteria and yeast were able to adhere to the wooden surfaces, although differences were observed according to strains and type of wood. It was evident that number of adhered cells of S. aureus was lower on spruce (3.62 × 103 CFU/mm2) compared to poplar and beech (1.09 × 105 and 2.11 × 104 CFU/mm2, respectively). Furthermore, oil and disinfectant promoted the adhesion of P. aeruginosa (155.93 and 130.50%, respectively) on the beech surfaces, while they had a strong inhibitory effect on the other tested microorganisms E. coli (87.44 and 88.44%, respectively), S. aureus (91.24 and 96.80%, respectively) and P. membranifaciens (92.45 and 87.24%, respectively). These findings are consistent with SEM micrographs. The current data also indicated that relative humidity and temperature significantly affected the adhesion of tested bacteria and yeast. The highest degree of adhesion was observed at a relative humidity of 98% and temperature of 20 and 37 °C for bacteria, or 20 and 27 °C for yeast. Thus, the knowledge of how these microorganisms adhere to wooden surfaces and which factors affect this phenomenon proves to be of great importance in order to avoid their colonization.